Barometer

ABSTRACT

A barometer comprising means for measuring atmospheric pressure, a barometric scale for indicating the measure atmospheric pressure, a scale pointer operatively connected to the measuring means and indicator means for directly indicating whether the atmospheric pressure is rising or falling. The indicator means is operated in response to movements of the measuring means to selectively give pressure rise and pressure fall indications.

United States Patent Fukumoto [151 3,654,808 [451 Apr. 11, 1972BAROMETER [72] Inventor: Shoichi Fukumoto, Osaka, Japan [73] Assignee:Fujiya Co. Ltd., Osaka, Japan [22] Filed: June 29, 1970 [21] Appl. No.:50,856

[30] Foreign Application Priority Data July 2, 1969 Japan ..44/52897[52] U.S. Cl ..73/384, 116/129 [51] Int. Cl. ..G0ll7/l2 [58] Field ofSearch "73/384, 386, 170, 129 NA;

[56] References Cited UNITED STATES PATENTS 1,995,436 3/1935 Schofield..73/386 2,007,680 7/1935 Hanscom ..73/386 739,126 9/ 1 903 Vives..340/266 FOREIGN PATENTS OR APPLICATIONS 1,213,478 4/1960 France..340/266 Primary Examiner-Donald O. Woodiel Attorney-Morgan, Finnegan,Durham & Pine 57 ABSTRACT A barometer comprising means for measuringatmospheric pressure, a barometric scale for indicating the measureatmospheric pressure, a scale pointer operatively connected to themeasuring means and indicator means for directly indicating whether theatmospheric pressure is rising or falling. The indicator means isoperated in response to movements of the measuring means to selectivelygive pressure rise and pressure fall indications.

1 Claims, 7 Drawing Figures BACKGROUND OF THE INVENTION This inventionrelates to a new and improved barometer. In particular, this inventionrelates to a new and improved barometer having a novel mechanism capableof indicating whether atmospheric pressure is rising or falling.

The mercury barometer and the aneroid barometer are the two mostpractical instruments for measuring the pressure of atmosphere. Thoughthe aneroid barometer does not have the reliability of a typical mercurybarometer, it has extensive use in homes, offices, hotels and otherliving places because of its portability and relatively small size.

An aneroid barometer generally comprises a vacuum box formed by a pairof corrugated thin metal diaphragms which are hermetically sealedtogether along their peripheries. One face of the vacuum box is boltedto the base of a casing while the other is connected to a scale pointerthrough a suitable mechanical linkage. Movements of the upper face ofthe vacuum box caused by changing air pressure are transmitted to thescale pointer so that pressures can be read directly against abarometric scale provided on a face plate.

The aneroid barometers are commonly used in homes and offices not onlyto obtain a barometric reading at a given moment but also to get someindication of the trend in the weather. As is generally known stormy andrainy weather is normally associated with low atmospheric pressure whilefair weather is characteristic of high atmospheric pressure. Thus, bytaking the barometric readings on the scale of the barometer andnoticing whether the pressure is rising or falling, it is possible tosome extent to predict the weather.

In order to attempt a weather forecast based on the atmospheric pressurechange it is important to observe the barometric tendency i.e. toobserve whether the barometric pressure is rising or falling. This couldbe done by reading the barometric pressure directly from the scalepointer from time to time and comparing them with each other to knowwhether the barometric pressure is rising or falling. This is, howeverextremely troublesome and time consuming. Moreover the change in theatmospheric pressure is relatively slow and no rapid or steep changeoccurs unless an extraordinary weather condition takes place.Accordingly, the rotational sweeping movement of the pointer over thebarometric scale on the face plate is also slow making it difficult fora user to notice the barometric tendency by a glance at the scalepointer. A suitable recording device can be incorporated into abarometer to write a record of atmospheric pressure change by moving apen over a chart paper. With this instrument the user may readily noticewhether pressure is rising or falling upon a glance at the chart paper.However, the barometer with such recording device does not provide asatisfactory solution since the recording device is complex inconstruction, difficult to operate and adds a substantial cost to theentire system.

Therefore, it is an object of this invention to provide a new andimproved barometer having means for indicating whether the atmosphericpressure is rising or falling in such manner as to enable the user tonotice it on a glance at the barometer.

It is another object of this invention to provide a novel mechanism forconspicuously indicating the barometric tendency which is simple inconstruction and can readily be incorporated into conventionalbarometers without causing a substantial design modification thereof.

It is still another object of this invention to provide a simple andinexpensive mechanism for conspicuously indicating whether theatmospheric pressure is rising or falling in response to the expansionand contraction movements of the vacuum box of a aneroid type barometer.

It is a further object of this invention to provide a new and improvedbarometer having a novel mechanism which is capable of indicating thebarometric tendency and eliminates the necessity of a recording device.

SUMMARY OF THE INVENTION In accordance with this invention an aneroidbarometer is provided with a mechanism capable of indicating whether theatmospheric pressure is rising or falling. In one preferred embodimentthe mechanism comprises a rotary member supported on a pointer shaftbetween a scale pointer and face plate for relative rotation with theshaft. A window or cut-out is formed in the scale pointer andcooperating markings for indicating whether the atmospheric pressure isrising or falling are provided on the rotary member at a radial positioncorresponding to the window. The scale pointer having the window thereinis connected in driving engagement to the rotary member such that themarking for the pressure rise may ap pear in the window during aclockwise rotation of the scale pointer while the marking for thepressure fall may emerge in the window during a counterclockwiserotation of the pointer.

In another preferred embodiment the indicator mechanism comprises anindicator plate having a pair of markings which indicate the barometricrise and barometric fall respectively. The indicator plate is rotatablysupported behind a window in the face plate and is connected in drivenengagement to a pinion fixedly mounted on the pointer shaft such that aclockwise rotation of the scale pointer may cause the marking on theplate for the pressure rise to appear in the window while acounterclockwise rotation may cause the marking for the pressure fall toappear in the window.

In still another embodiment the mechanism comprises a pair of indicatorlamps. The lamps are electrically connected through mechanical switchingmeans to a suitable power supply. The switching means operates inresponse to the movements of the scale pointer or vacuum box of thebarometer to selectively energize the indicator lamps. Energization ofone lamp indicates that the atmospheric pressure is rising whileenergization of other lamp indicates the pressure is falling.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings:

FIG. 1 is a cross sectional view of a typical aneroid barometer showingschematically the construction thereof;

FIG. 2 is a plan view of an aneroid barometer including a novelmechanism for indicating the barometric tendency according to one formof this invention and shows said mechanism is indicating a barometricpressure rise;

FIG. 3 is a view similar to FIG. 2 showing said mechanism indicating abarometric pressure fall;

FIG. 4 is a plan view, partially cut away, of an aneroid barometerincluding a novel indicator mechanism according to another form of thisinvention and shows said mechanism indicating an atmospheric pressurerise;

FIG. 5 is a view similar to FIG. 4 showing the mechanism indicating anatmospheric pressure fall;

FIG. 6 is a schematic view of an electric indicator mechanism accordingto still another form of this invention; and

FIG. 7 is a schematic view of an electric indicator mechanism accordingto still another form of this invention together with associated partsof the barometer mechanism.

Like references are used to designate like parts all through thefollowing embodiments of this invention.

Turning now to the drawings in detail, the preferred embodiments of thepresent invention have been illustrated in connection with theconventionally known aneroid barometer without necessarily limiting thescope of the invention thereto. FIG. 1 schematically shows a typicalform of the aneroid barometer which comprises a vacuum box 10 positionedwithin a casing 12. The vacuum box is formed by two corrugated thinmetal diaphragms l4 and 16 hermetically sealed together along theirouter peripheries by means of welding, brazing or the like. The centerof the lower metal diaphragm 16 is secured to the base or bottom of thebarometer casing while the center of the upper metal diaphragm 14 isconnected to a shaft cylindrical rod 18 which supports the free end of aleaf spring 20. The other end of the spring 20 is fixedly secured to asupport block 22 which is mounted also to the bottom of the casing 12.With this arrangement the free end of the leaf spring 20 normally biasesthe vacuum box 10 into its expanded condition against atmosphericpressure. A rise in the atmospheric pressure causes the upper face ofthe vacuum box 10 to depress or move downwardly toward the lower face ofthe box while a fall in the atmospheric pressure permits the upper faceof the FIG. 6) vacuum box to expand or move upwardly away from the lowerface under the influence of the biasing force of the spring 20. Thus,the upper face of the vacuum box 10 moves vertically up and down inresponse to changing atmospheric pressure. Movements of the upper faceof the vacuum box are transmitted to a scale pointer 24 through asuitable mechanical linkage which, in the illustrated barometer,includes a connecting rod 27, a chain 28 and a recessed wheel 30. Up anddown movements of the upper face the vacuum box, 10 raise and lower therod 18. The movement of the rod 18 is converted through the linkage intoa rotational movement of the pointer 24 and a barometric reading isobtained against a scale on a face plate 26.

FIGS. 2 and 3 show an aneroid barometer embodying one preferred form ofthis invention. The barometer includes a face plate 26 which has markedthereon a suitable pressure scale 32. A shaft 34 projects outwardly inthe center portion of the face plate 26 to support scale pointer 24. Ashereinabove explained in connection with FIG. 1, expansion andcontraction movements of the vacuum box caused by atmospheric pressurechanges are transmitted to the shaft 34 to rotate the same. Since thepointer 24 is fixedly mounted on this shaft, a rotational movement ofthe shaft causes a simultaneous rotation of the pointer with its freeend sweeping over the barometric scale 26 to provide a barometricreading. A circular window 36 is formed in this scale pointer for thepurpose hereinafter described in detail.

In accordance with the present invention a disc 38 is mounted on theshaft 34 between the face plate and pointer for relative rotationalmovement with respect to the shaft. An indication mark 40 in the form ofan arcuate strip having an arrow at both ends is provided on the rotarydisc 36 at a radial position generally corresponding to the circularwindow 36 in the scale pointer. The arrow ended mark 40 is provided toindicate the barometric tendency and has an angular extension or lengthlonger than the diameter of the window 36. As shown in a dotted line ashort pin or projection 42 is attached to the back of the pointer toextend into a cooperating arcuate slot 44 formed in the rotary disc 38.

With this arrangement of the barometer when atmospheric pressure risesthe scale pointer 24 is driven by the support shaft 34 to rotate inclockwise direction. A slight clockwise rotation of the pointer bringsthe rear projection 42 into engagement with the right edge of thearcuate slot 44. At this moment, as shown in FIG. 2, the right handarrow of the arrow ended mark 40 on the rotary disc appears in thewindow 36 of the scale pointer indicating that the air pressure isrising. A continued rise in the atmospheric pressure causes the scalepointer to move further in the clockwise direction thereby pushing therotary disc in the same direction. Accordingly, as long as theatmospheric pressure rises the left hand arrow continues to appear inthe window 36 of the scale pointer, thereby conspicuously indicatingthat pressure is rising. On the other hand, when the atmosphericpressure changes to fall the scale pointer 24 is driven incounterclockwise direction and after a slight counterclockwise rotationof the pointer its rear projection 42 comes into engagement with theleft edge of the arcuate slot 44. At this time the left hand arrow ofthe arrow ended mark 40 emerges in the window of the pointer as shown inFIG. 3. A continued fall in air pressure drives the scale pointer 24 torotate further in counterclockwise direction carrying together therotary disc 38 in that direction. Thus, during atmospheric pressure fallthe left hand arrow continues to appear in the window 36 of the scalepointer and clearly shows that the pressure is falling. With thisconstruction of the barometer, the barometric tendency is soconspicuously indicated by the arrows of the marking 40 whichselectively appear in the window that the user may readily notice on amere glance at the window 36 whether the atmospheric pressure is risingor falling at a given moment. This successfully saves the user thetroublesome work of taking barometric readings from time to time to knowthe trend in pressure changes. The window 36 in the scale pointer, themarking 40 on the rotary disc and the slot 44 in the disc are notlimited in their shape and size to those illustrated in FIGS. 2 and 3and any suitable form and size may be selected for them. The onlyessential point in this indicator arrangement is to dispose the slot andprojection with respect to the marking and window such that the righthand arow of the marking may appear upon a slight clockwise rotation ofthe scale pointer while the lefthand arrow may appear upon a slightcounterclockwise rotation of the pointer. Also, in this connection theangular extension of the slot must carefully be selected in relation tothat of the marking on the face plate. Further for a quick indicativeexchange in response to the reversal of the barometric change the slot44, marking 40 on the rotary disc and window 36 may preferably be formedto have a small angular dimension.

FIGS. 4 and 5 illustrate an aneroid type barometer embodying anotherform of this invention. In this embodiment the barometric tendencies areshown by colored markings instead of the arrows. As shown in thedrawings, the face plate 26 is provided at a proper position with acircular window 46 and a sector plate 48 is mounted at the back of theface plate to cover the circular window. More specifically, the sectorplate 48 has an area] dimension at least twice as great as that of thewindow and is pivoted by a pin 50 to the back surface of the face plate.The sector plate is further provided at its apex with a projection 52which is in operative engagement with a pinion 54. The pinion is fixedlymounted on the shaft 34 at the back of the face plate 26 for rotationtherewith. Clockwise or counterclockwise rotation of the shaft 34 causedby changing air pressure is transmitted through the meshing engagementbetween the pinion 54 and projection 52 to the sector plate 48 which isrotatably supported by the pin 52. Thus, as the shaft rotates togetherwith the scale pointer 24 the sector plate 48 is driven towards itsright position as shown in FIG. 4 and its left position as shown in FIG.5 depending upon the direction of rotation of the shaft. The arealdimension of the window 46 being less than half of the areal dimensionof the sector plate 48, the sector plate is disposed with respect to thewindow such that the right half portion of the sector plate may appearin the window in its leftmost position and conversely the left halfportion of the sector plate may emerge in the window as the plate movesinto the rightmost position. For the ease of discrimination, two halfportions of the front sector surface may preferably be painted orotherwise be coated in distinct different colors, for example, red forthe right half and blue for the left half.

With this indicating arrangement, as the scale pointer 24 moves inclockwise direction in response to the rise in atmospheric pressure italso drives the sector plate 48 to rotate in counterclockwise directionon the pin 50. Upon a predetermined range of the barometric change thesector plate is moved into its rightmost position and the blue coloredleft half of the sector surface appears in the window 46 as shown inFIG. 4 to thereby noticeably show the rising barometric tendency. As theatmospheric pressure beings to fall the, pointer 24 moves incounterclockwise direction and the sector plate is driven throughoperative engagement between the pinion 54 and projection 52 inclockwise direction. When this barometric fall reaches a predeterminedrange the sector is rotated into its leftmost position as shown FIG. 5and the red colored right half of the sector plate appears in the window46 indicating that the pressure is falling. The user has only to glanceat the window 46 in order to notice whether the barometric pressure isrising or falling;. In this embodiment as in the previous one, relativesize and positioning of the pinion, projection,

sector plate and window must suitably be selected so that a slightangular displacement of the scale pointer after a reversal of rotationcaused by atmospheric pressure change may effectively change theindication in the window.

In the above described two embodiments of this invention mechanicalmeans are used to show the indication of the barometric tendency in thewindow in response to angular displacement of the scale pointer. Aspointed out above, some difficulty may arise with the mechanicalindication in obtaining the quickest possible indicative response to thereversal of the barometric change. That is, a complete change of theindication in the window is not effected until a predetermined range ofbarometric change is reached after the reversal of the pressure changefrom rising to falling tendencies or from falling or rising tendencies.If the barometric change is extremely slow it may take some time beforethe indication is completely interchanged. Or, if the barometric changedoes not reach a predetermined range, the indication may not becompletely interchanged and an incomplete or indefinite indication mayappear in the window making it difficult for the user to know whetherthe pressure is rising or falling. These difficulties can besuccessfully avoided as explained above by a suitable selection of therelative position and dimension of the constituent parts of theindication mechanism. However, for a more complete and highly responsiveindication mechanism electrical means may preferably be employed.

In FIG. 6 there is illustrated another mechanism for indicating whetherthe atmospheric pressure is rising or falling which includes electricalmeans and which can readily be incorporated into the aneroid barometer.The mechanism comprises switching means including an electricallyconductive movable contact 56 fixedly mounted on the pointer shaft 34.The movable contact has a pair of opposite contact surfaces 56a and 56b.A split conductive ring 57 is supported for free follower motion withrespect to the movable contact 56. As shown in the drawing the followingring 57 is formed by a pair of semicircular ring segments 58 and 60.Segments 58 and 60 are attached together but electrically insulated fromeach other by an insulation 62. The follower ring is disposed withrespect to the movable contact 56 such that two end contact surfaces 64and 66 of the ring may respectively face the contact surfaces 56a and56b of the movable contact with a close gap therebetween. As the movablecontact rotates in either clockwise or counterclockwise direction itengages one end surface of the follower ring 57 and pushes the ringalong with it. level The electric indication mechanism further includesa pair of indication lamps 68 and 70 and a suitable power source E. Oneterminal of the first lamp 68 is connected through a conductor 72 tosemicircular ring segment 72 while the other terminal of the lamp isconnected through a lead conductor 74 to one terminal of the powersupply E. One terminal of the second lamp 70 is connected through a leadconductor 76 to ring segment 60 while the other terminal is connectedvia a conductor 78 to one terminal of power supply E. The other terminalof power supply E is joined to the movable contact element 56.Indicating lamps 68 and 70 may be disposed on the face plate (not shown)at suitable locations and may have different colors for the same purposeas hereinabove explained.

With this indicating arrangement, as the scale pointer (not shown) movesin clockwise direction in response to a rise in atmospheric pressure,the movable contact mounted on the pointer shaft 34 also moves inclockwise direction. Only a slight rotation of the pointer in thatdirection brings contact surface 56b of the movable contact into directengagement with end surface 66 of the ring segment 60, therebyestablishing an electrical circuit from the ring element 60 throughconductor 76, second lamp 70, conductor 78, power supply E, movablecontact 56 and back to the segment 60. The second lamp 70 is thus turnedon to indicate the barometric pressure is rising. As long as thebarometric pressures rises the scale pointer continues to move in theclockwise direction keeping the contact surface 56b in pushingengagement with the end surface 66. The second lamp is kept turned on.When the barometric pressure turns to fall the scale pointer togetherwith the movable contact element 56 reverses its rotational movement. Asthe result, the contact element 56 moves away from the end surface 66 ofthe ring segment breaking the electric circuit through the secondindication lamp 70 and the lamp is turned off. A continued fall inatmospheric pressure causes the contact element 56 to rotate further incounterclockwise direction and brings the other contact surface 560 ofthe movable contact element in engagement with end surface 64 of thering segment 58. This establishes an electric circuit from ring segment58 through conductor 72, first indicator lamp 68 conductor 74, powersupply E, movable contact 56 and back to ring segment 58 turning thelamp 68 on to indicate the atmospheric pressure is falling. The movablecontact element 56 is kept in pushing engagement with the end surface 64and the first lamp is held turned on while the pressure falls. Anotherreversal of the pressure change moves the contact element 56 away fromthe end surface 64 toward the other end surface 66 in the same manner asexplained above and the lamp 68 is turned off as the result of abreakage in the circuit therethrough between contact surfaces 56a and64.

Upon a look at the indication lamps the user may readily notice whetherthe atmospheric pressure is rising or falling. In this embodiment it isalso possible to cut out a pair of oppositely directed arrows in theface plate which indicate rising and falling pressure respectively andto light these cutout arrows by the indication lamps 68 and 70,respectively:

FIG. 5 illustrates another form of an electrical indication mechanismaccording to this invention. As shown in the drawing, an elongatedhorizontal contact blade or strip made of a conductive material isconnected to the vertical rod 18 which is attached to the uppercorrugated metal diaphragm 14. As is already explained in connectionwith FIG. 1, the rod moves vertically along its axis according to theexpansion and contraction movements of the vacuum box 10 caused bychanging air pressure. Near the free end of the contact blade 80 thereis positioned an electrically conductive split ring 57 with two endsurfaces 64 and 66 facing in close proximity to the correspondingsurfaces of the contact blade. The conductive follower ring 57 isrotatably supported and comprises a pair of ring segments 58 and 60which are mechanically attached together but are electrically insulatedfrom each other by an insulation 62 interposed therebetween. Theindication mechanism further includes first and second indication lamps68 and 70. The electric circuit involving these lamps is substantiallysimilar in construction to that shown in FIG. 6. Accordingly, nodetailed description is given with respect to the circuit construction.

In operation, as the atmospheric pressure rises a contraction of thevacuum box 10 pulls the rod 18 vertically downward. Upon a slightdownward motion of the rod the free end of the elongated contact blade80 engages the lower end surface 66 of the follower ring 57 to completean electric circuit through the second lamp 70 in the same manner asexplained above. The lamp is then switched on to indicate the pressureis rising. Conversely, as the atmospheric pressure changes to fall an expansion of the vacuum box 10 moves the rod 18 vertically upward bringingthe free end of the contact blade 80 away from the lower end surface 66into engagement with the upper end surface 64 of the follower ring. Theelectric circuit through the second lamp 70 is broken and an electriccircuit through the first lamp 68 is then completed to turn this lampon, which indicates the pressure is falling.

In these two embodiments which have electrical means incorporatedtherein it is easy to reduce the gap or space between the two facingcontact surfaces to a minimum. With such minimum gap between the facingsurfaces the slightest mechanical displacement of the movable contact orcontact blade is required to effect the desired switching operation.Phrased differently, a small atmospheric change as detected by thevacuum box can operate the indicator lamp circuit through the movablecontact element or contact blade to selectively turn on the lamps sothat a delayed indicative response as mentioned above could successfullybe avoided.

By employing suitable integrator or difi'erentiator means on in thedescribed mechanism it is possible to indicate the rate and amount ofatmospheric pressure change.

While only a few preferred embodiments have been described above, it isto be understood that this invention is not limited to the particularembodiment disclosed and that it is intended to cover all modificationswhich are within the true spirit and scope of this invention as claimed.

What is claimed is:

l. A barometer comprising:

a casing;

a face plate fixedly mounted in the casing;

a barometer scale peripherally disposed on the face plate;

a rotatable shaft extending through the face plate;

a scale pointer fixedly mounted on the rotatable shaft for sweepingmovement over the face plate;

means for rotating the scale pointer in one direction as the atmosphericpressure rises and in the opposite direction as the atmospheric pressuredrops;

a window fonned at a fixed position in the face plate;

a gear fixedly mounted on the rotatable shaft for coincident movementwith the scale pointer;

a pivotally mounted sector plate about twice the areal size of thewindow, which sector plate is located under the window;

a left hand side of the sector plate having a first color;

a right hand side of the sector plate having a second color;

and

a tooth integrally formed with the sector plate extending from the pivotmount of the sector plate, in a direction directly opposite the sectorplate, to the gear for engagement with the two teeth in alignmenttherewith;

whereby rotation of the scale pointer in a clockwise direction will beaccompanied by rotation of the sector plate to urge the right hand sideof the sector plate into registry with the window and rotation of thescale pointer in the counterclockwise direction urges the left hand sideof the sector plate into registry with the window.

1. A barometer comprising: a casing; a face plate fixedly mounted in thecasing; a barometer scale peripherally disposed on the face plate; arotatable shaft extending through the face plate; a scale pointerfixedly mounted on the rotatable shaft for sweeping movement over theface plate; means for rotating the scale pointer in one direction as theatmospheric pressure rises and in the opposite direction as theatmospheric pressure drops; a window formed at a fixed position in theface plate; a gear fixedly mounted on the rotatable shaft for coincidentmovement with the scale pointer; a pivotally mounted sector plate abouttwice the areal size of the window, which sector plate is located underthe window; a left hand side of the sector plate having a first color; aright hand side of the sector plate having a second color; and a toothintegrally formed with the sector plate extending from the pivot mountof The sector plate, in a direction directly opposite the sector plate,to the gear for engagement with the two teeth in alignment therewith;whereby rotation of the scale pointer in a clockwise direction will beaccompanied by rotation of the sector plate to urge the right hand sideof the sector plate into registry with the window and rotation of thescale pointer in the counterclockwise direction urges the left hand sideof the sector plate into registry with the window.